History

Born a Frost Giant during the last great war between Asgard and Jotunheim, Loki was abandoned by his actual father, Laufey, and left to die due to being born too small for the giant’s liking. Odin found and adopted the baby without hesitation and took him to Asgard, where Loki would grow up as a prince to the Realm Eternal, unaware of his own heritage until more than thousand years later, on the very day that was supposed to be the day of Thor’s coronation.

By that time Loki has grown into a bitterly withdrawn young man with hardly any self-worth but a massive inferiority complex combined with plenty of jealousy for his older, perfect brother. But also a man who has learned to hide all these things behind mischief and tricks. It is his jealousy that causes Loki to sabotage Thor’s day of triumph and ultimately set in motion a chain of events that will change not only the lives of both brothers, but also how they perceive themselves and those around them.

While for Thor this means a change of heart in a more favorable and heroic direction, Loki loses his grip on everything he once held dear and begins to fall away until he gets quite literally swallowed by the void.

He discovers that he is a Frost Giant, and this discovery shatters his entire world and his beliefs. Even the reassurances of Odin and later Frigga do little to change this. So when Odin falls into the Odinsleep and, due to Thor being banished to Earth, Loki actually becomes the temporary King of Asgard, he just feels the more eager to prove himself. Just as he feels the more eager to actually end his brother and secure his own place on the throne.

Loki’s attempt on Thor’s life, however, is just what the older brother needs to prove his worthiness and regain his powers by sacrificing himself to save his old and new found friends along with the remaining people in that small town threatened by the Destroyer Loki send after him. Baiting Laufey to Asgard only to slay him, though, works out just fine and Frigga even is grateful for Loki saving Odin's life- until Thor shows up to confront Loki and bring light to his schemes. This only causes Loki to rush off to the Bifröst and attempt to use it to tear apart Jotunheim and bring about the end of all Frost Giants. All in some odd hope of still proving himself to Odin and finally become a worthy son.

While, clearly, Loki’s sanity is already somewhat questionable at this point, to say the least, he still harbors hope to gain his father’s approval even while fighting Thor and attempting genocide. This hope lasts on until Thor destroys the Bifröst to save Jotunheim, causing both brothers to be thrown off the bridge with Odin being the one to catch them. It is then that Loki acknowledges Odin as his father for the last time and that Odin shatters all what is left of his adopted son’s hopes and beliefs. And Loki lets himself fall into the void, being assumed to have gotten killed by that action.

An unknown amount of time passes between the events of Thor and The Avengers. Time that Loki spends trapped between dimensions, finding himself tossed into unknown worlds until he eventually ends up with Thanos and the Other and strikes a deal with them to acquire the Tesseract for them in exchange for Earth.

Loki’s attack on Earth begins with an attack on SHIELD, who happens to be in possession of the Tesseract. A powerful relict and one of the infinity gems, harboring unlimited power. The Asgardian gives a decent display of just how little of a bother the firepower of modern earthly weapons is to him while taking out what likely happen to be SHIELD’s finest trained guards. With little effort he acquires the cube and brainwashes a couple of SHIELD’s personnel to ensure his escape.

Little does he know by then that his actions are about to bring yet another significant change. This time for Earth: The Avengers are put together to stop Loki’s little invasion. Yet, these heroes do not work together too well at first. Only after the Trickster gets his hands into the game once more, wrecks some havoc on SHIELD’s Helicarrier and kills Agent Coulson it is that they begin to come together and work and function as a team.

The Avengers may not be able to stop Loki from unleashing his borrowed army of Chitauri on New York, but they do defeat the threat in the end, capture Loki and he gets handed back to Asgard to face Asgardian justice.

Personality

Loki is the God of Mischief and bringer of chaos and change. The Lie-Smith. The Trickster that cannot be trusted. And this is nothing he is intentionally, but this is what he actually is. It’s the core of his being and his one true nature. He lies more often than telling the truth. Especially to himself.

This doesn't necessarily make him evil, though. His actions just aren’t always good and much rather tend to involve a disastrous development that is bound to overshadow whatever positive side effects it brings along. Generally he is willing to work with either side, good or bad, depending on which will get him towards his personal goal. So one may rather see him as neutral. He works hard and meticulously to set up a disaster only to watch ruefully when it actually unfolds and then finds himself torn between triumph and terror until his pride makes him choose triumph. Because he desperately tries to prove himself. Which seems to be his endless quest.

At first he wanted to prove himself to his father. To show Odin that he is just as worthy as his brother Thor, who Loki has always been jealous of and still reacts unnerved just by having someone else drop his name. From his perception Odin had favored Thor over him, but later it will show that Loki’s perception doesn’t necessarily equal the truth. For example when he accuses Thor of having tossed him into the void when it was actually himself letting go of Gungnir that had him fall. There is a decent chance that some of his memories aren't exactly true anymore but got screwed up in one way or another while he was assumed dead.

When Thor was banished from Asgard (thanks to Loki’s actions) and Odin fell into the Odinsleep (partly thanks to Loki’s actions), Loki became King of Asgard for a short period of time. A deleted scene in which he is given Gungnir, Odin’s spear, as sign of his reign over Asgard actually shows him surprised by this decision, if not even unprepared for it. Whilst the throne had been what he had claimed to want, he really mostly had just wanted acknowledgement. Furthermore by that point he had considered it impossible for him to become Asgard’s King due to his newfound knowledge about his true heritage as a Frost Giant and his adoption by Odin. So here he saw a chance to prove himself… But chose the presumably worst way to attempt to do so: By being who he is and telling different lies to different people, making false allies just to backstab even those. Ultimately he proved nothing, but lost the trust of everyone he cared about and finds himself swallowed by the void.

What we learn from this is that he tries. He tries hard and he tries a lot, but he has an unhealthy tendency to… Fail. Things blow up in his face, he gets beaten up or shot when in the middle of a speech and anyone that had to deal with him at least once will make sure to not trust him easily if at all.

It is stated at one point that winning isn’t part of his nature, which appears to be true. In some twisted way he is bound to fail by who and what he is. He creates mischief and chaos. But chaos can only last so long and letting it swallow up everything won’t work because next to chaos and discord Loki is also supposed to bring change. And change is what is happening after chaos has set in and got settled. It’s like a circular flow and his actual purpose: To make things change. And as confusing as this may sound, there is a sort of logic behind it, but it is very unlikely that Loki himself is even aware of this. Or ever should become aware of it. Because he still has to do what he does, but in order for him to fulfill his purpose he needs motivation. And that motivation he draws from his constant failing.

And there we also have what makes him discontent. With himself most of all. He is eager to succeed and constantly compares himself to his brother but regardless of how well he does, regardless how well he has everything planned out… He won’t succeed. And if he does, it doesn't last.

Loki is very unlike his brother. He observes, he thinks, he listens and ponders. Also he is very secretive about what is going on in his head and especially about his feelings. He prefers to hide them as best as possible since actually he happens to be quite emotional. And that’s not exactly a trait that suits a male Asgardian.

The male Asgardian is supposed to be manly, strong, huge, wield impressive weapons, go to war for a while to slay some opponents and return to get drunk and feast and just… Be manly. Viking Gods and all.

Now as for Loki… He doesn’t really fit into that image if we are honest. Compared to a human he may be strong, but he sure doesn’t come along packed with muscles as Thor does and compared to other Asgardians his strength clearly is a lot less impressive. He doesn’t swing brute weapons for bloody slaughter but fights the sneaky, feminine way with his magic, little daggers and tricks. And even if we tilt our head and squint our eyes I doubt that anyone can truly picture him getting helplessly drunk and loud and obnoxious at a proper feast. So by Asgardian standards he is a pretty poor example for a man. But at least that he might actually be aware of. Which is why he makes sure his emotional side is well-hidden.

And yet we see it peeking through every now and then. Several situations have brought him to the brink of tears and Loki fails to hold them back in his rage when fighting his brother, revealing to him that he only ever wanted to be his equal. And later, every time Thor offers him to return back home with him: Loki hesitates. He hesitates, clearly torn between actually wanting to and his stubbornly prideful obsession with wanting to succeed. And he keeps choosing pride.

It also shows when his mother, Frigga, is killed and Loki not just makes a mess out of his cell, but also himself. He hadn’t parted with her on good terms and partly blames himself for her death: By having been imprisoned during the attack (due to his own actions) and therefore having been unable to potentially protect her. A lesser point may be that he indirectly assisted her killer by hinting him the right way out, promising himself to just cause some trouble for Thor.

Just another point on the long list that Loki failed to do right, but one that pains him especially. Up until the very end Frigga remained the one that still believed in him and wanted to trust him even when Loki already refused to consider her his mother any longer. Which was a claim he didn’t mean earnestly if his grief is any indication.

He loved his mother. He wanted her to be his mother. And he loved his family and wanted them to acknowledge him and be proud of him. But with the loss of his family all that remained was his need for acknowledgement that grew into a desire for power. An urge to be superior and rule and be an actual God, a king with a kingdom, worship and unquestioned reign.

Humans he considers to be lesser beings. Unworthy and at best useful as toys for his schemes. Loki will act high and mighty, not rarely sarcastic and in a playfully condescending manner unless actually getting ticked off. Which happens to be the case when his plans don't work out to his liking and he is about to fail. Then he loses all composure, sets his actual anger and frustration free and even starts yelling, insisting on his superiority and godhood. Not that this sort of behavior helps him any, it merely displays how bad he can deal with things slipping his control and him having to realize that he is, in fact, not almighty.

Abilities

First of all, he’s a god. As such he can easily live for thousands of years, but by no means is actually immortal. The gods of Asgard age and die, but when they die it rarely happens due to old age.

The Asgardian language it the all-tongue. It automatically translates into the native tongue of those listening to it and lets the user understand and language spoken to them. Convenient as this may be, these translations tend to be very literal and can lead to general confusion and sometimes even misunderstandings.

Further, Loki possesses superhuman strength, durability and reflexes. Being born a frost giant he also withstands extremely cold temperatures without being bothered by the cold at all. This also leaves him with a whole ice-based skillset unique to frost giants that he has no real control over as he has not yet researched these abilities.

Like all Asgardians Loki has a very high body density, which not just makes him a lot heavier than he looks, but also pretty much bulletproof, fireproof and it is extremely difficult to even put a scratch into his skin. Even a severe beating from the Hulk himself merely leaves him winded and with but a couple of bruises. An explosion directly to his face? Yes, that leaves a little scratch, thank you. On top of that Asgardians also heal a lot faster, so even a seemingly lethal wound with a weapon that actually can harm them does not necessarily kill them.

Loki is a skilled combatant and strategist and mainly uses throwing daggers, spears and his magic to fight. When he fights, he fights dirty. He likes to perform sneak attacks and uses illusions to trick his opponents rather than directly defeating them with his actual weapons. While he shows a great deal of magic knowledge, he isn’t often seen using any greatly offensive spells save for some energy bolts usually fired from his spear. Rather he uses the aforementioned illusionary magic or such that assist him in his manipulating efforts, which does include actual mind control as well. He also uses his magic for seemingly trivial things, such as changing his clothes, summoning his weapons or turning a goblet of wine into a goblet filled with tiny snakes for his personal amusement.

Magic comes naturally to Loki and he uses it in whatever way he pleases without being limited to certain spells.

But before all sorcery and combatant skills comes his tongue. He is very intelligent and has the ability to talk his way out of dire situations and weaves his net of lies without missing a beat. This presumably has saved him his hide more than once. Especially in addition to his ability to adapt to new situations fast and learn quickly.

And lastly, he is a shape-shifter. Meaning that he can assume different forms at will. This can be people, animals, beasts and generally anything of either gender.